The London club rose to prominence over the last ten years after being bought by Russian billionaire Roman Abramovich, and the oligarch’s wealth has seen the Stamford Bridge side claim a host of trophies ever since, including last season’s league title.

Some of Chelsea’s rivals have spent big in the transfer market so far this summer and Mourinho has lamented the fact that the teams around him are using the cheque book so willingly.

“In the beginning of Mr Abramovich coming to Chelsea, Chelsea was buying the title,” Mourinho said to ESPN.

"Now, they are buying the title. All of them, they are buying the title. It is up to us to be strong and to fight them and, obviously, to try and win it again, even without the big investments."

While Chelsea have been relatively quiet in the transfer market so far this summer, many have pointed out that as recently as last season, Mourinho spent heavily in acquiring Diego Costa and Cesc Fabregas, who proved crucial last season’s league-winning campaign.